function check(){
                            var email=document.form_new_password.email.value;
                            var answer = document.form_new_password.answer.value;
                            var errorLog=document.getElementById("new_password_error_log");
                            var email_reg_exp = /^([a-zA-Z0-9_\.\-])+\@(([a-zA-Z0-9\-]{2,})+\.)+([a-zA-Z0-9]{2,})+$/;
                            //Effettua il controllo sul campo email
                            if (!email_reg_exp.test(email) || (email == "") || (email == "undefined")) {
                                document.form_new_password.email.focus();
                                errorLog.innerHTML='email is invalid.'
                                return false;
                            } else if ((answer== "") || (answer== "undefined")) {
                                errorLog.innerHTML='Insert the answer for the captcha.';
                                document.form_new_password.answer.focus();
                                return false;
                            } else {
                                document.form_new_password.submit();
                            }
                        }